Leading judges said today that they are “acutely aware of the desperate situation” of those at the centre of “right-to-die” litigation at the Court of Appeal - but emphasised that the case could not be decided on the basis of “personal sympathy”.

The Lord Chief Justice, Lord Judge, sitting with two other judges in London, made the comments at the outset of the latest round of legal action started by Tony Nicklinson, who died at home in Melksham, Wiltshire, a week after he lost a High Court bid in August to end his life with a doctor's help.

His widow Jane vowed to continue the battle in the courts, which she said was “part of Tony's legacy”.

Lord Judge, sitting with the Master of the Rolls Lord Dyson and Lord Justice Elias, will hear argument in three cases over the course of several days.

He said: “We are acutely aware of the desperate situation in which the appellants find themselves, and we are very sympathetic.”

But he stressed that “we cannot decide this case as a matter of personal sympathy”.

It has to be decided on the “basis of principles of law” after the court has heard all sides.

As well as a challenge by Mrs Nicklinson against the High Court's ruling, the judges will hear submissions on behalf of paralysed road accident victim Paul Lamb, 57, from Leeds - who won the right to join the litigation to continue the fight started by Mr Nicklinson.

They will also be hearing a challenge by another man, whose case was rejected at the High Court on the same day as Mr Nicklinson's.

The locked-in syndrome sufferer, who cannot be identified for legal reasons but is referred to as “Martin”, suffered a massive stroke in August 2008. He is unable to speak and virtually unable to move, describing his life as “undignified, distressing and intolerable” - and wants to be allowed a “dignified suicide”.

Mr Lamb is immobile except for limited movement in his right hand and has been in significant pain since the 1990 tragedy.

The former builder and father-of-two wants a doctor to help him die in a dignified way, preferably by a lethal injection, with his family around him in his own home. He says he feels worn out and fed up with going through the motions of life rather than living it.

Mr Lamb, who is present in court for the hearing, said before it began that he hoped the judges would listen.

He said: “I'm not confident because I've seen the legal system. It's already failed people.

“You can never be confident. I feel the legal system doesn't listen and I think they should listen more.”

He added: “They will listen today is what I'm hoping. I'm confident in my solicitor and barrister. I think the public will sympathise. Definitely.”

Mrs Nicklinson, who is also in court, commented yesterday: “We are really excited that we are back in court and hopeful that we will win the appeal and have the case heard again.

“We are hoping that the judges will see that we didn't get a fair hearing last time and that we should get the case heard again. We feel that our case wasn't properly heard.”

Mr Nicklinson, who was paralysed by a stroke while on a business trip to Athens in 2005, had refused food and contracted pneumonia after he was "devastated" by the decision of Lord Justice Toulson, Mr Justice Royce and Mrs Justice Macur.

He had sought declarations that there should be a defence of necessity available to a doctor assisting him to die, and that the law was incompatible with his right to respect for private and family life under Article 8 of the European Convention on Human Rights, which he argued includes a right to autonomy and self determination at the end of life.

Paul Bowen QC, representing Mrs Nicklinson and Mr Lamb in their cases against the Ministry of Justice, told the appeal judges that the High Court had "rejected the claims because, in summary , it considered Parliament, not the courts, should be responsible for changing the law in this area".

He said the High Court "did not decide the substantive issues at the heart of the claims" of whether the current law does "disproportionately interfere" with the appellants' Article 8 rights, nor whether the defence of necessity is available to a doctor providing the assistance to die.

Mr Bowen said: "This appeal is about the constitutional issues, not the substantive issues.

"If the appeal is successful on those constitutional issues, the appellants seek an order setting aside the order of the Divisional Court, ordering a retrial and remitting the matter back for the substantive issues to be determined..."

Law firm Bindmans said Mrs Nicklinson has taken over the Article 8 claims in her own right and as the administrator of the estate of her late husband.

Mr Lamb is pursuing the Article 8 claims in his own right and a claim that the common law defence of necessity should be available to a charge of murder where a doctor assists a person such as himself to end his life.

Leigh Day, the solicitors representing 48-year-old Martin, say that in his case they will argue that there should be a change to the approach taken to prosecution for assisted suicide as, although it is legal to commit suicide, it is a serious criminal offence to assist someone to take their own life.

Leigh Day said current Director of Public Prosecution (DPP) guidance makes it clear that friends or family members would be unlikely to be prosecuted.

But Martin's wife does not wish to be actively involved in the steps necessary to bring about his death and so he needs the assistance of a professional, most likely a doctor, nurse or a carer, to help him to die.

The law firm said that currently the DPP policy does not make it clear that such people are unlikely to be prosecuted.

Giving the background to the case, Mr Bowen said Mr Nicklinson's condition had not been life-threatening and he had a reasonable expectation of living "many more years".

"That was a prospect which he gradually determined was not one he wished to face. He made a competent and rational decision to end his own life," said the QC.

He added: "However, by virtue of his almost total physical disability, he was unable to act upon that wish, other than by refusing all food and liquids and thereby dying of dehydration.

"He required medical assistance to end his life, which would inevitably involve the assister committing the criminal offence either of assisted suicide or murder.

"Mr Nicklinson was barred by operation of the criminal law from obtaining assistance to end his life. He brought high-profile proceedings challenging this state of affairs."

Mr Bowen said that following the High Court's decision to dismiss his claims Mr Nicklinson refused nutrition, fluids and medical treatment and died of pneumonia on August 22.

Referring to Mr Lamb, who is divorced with two grown-up children, Mr Bowen said he requires constant care and has carers with him, funded by the local primary care trust, 24 hours a day.

"He spends the whole of every day in his wheelchair. He experiences a significant amount of pain and has done ever since the accident, with the consequence that he is constantly on morphine.

"He feels that he is trapped in his body, that he cannot enjoy or endure a life that is so monotonous and painful and lacking in autonomy.

"He wishes a doctor to end his life and seeks the same declarations originally sought by Tony Nicklinson in the proceedings ..."

The British Humanist Association (BHA) is also a party to the case, as an intervener on the side of assisted dying.

BHA chief executive Andrew Copson said: "The brave individuals bringing these cases are overcoming great personal tragedies in order to advance justice and bring about a more humane society and we are proud to be parties to their cases in support of them.

"When a mentally competent adult is suffering incurably, is permanently incapacitated, and has made a clear and informed decision to end their life but is unable to do so independently, simple compassion calls out to us to give assistance - it's the right thing to do.

"That's what the overwhelming majority of the British public believe, and we think the law should reflect that."

Yogi Amin, of law firm Irwin Mitchell, acting on behalf of the BHA, said: "The law should be certain and reflect modern society.

"Both Parliament and judge-made law should develop to allow for personal autonomy."

Mr Bowen told the court that the case was not just concerned with "autonomy".

He said: "Another fundamental right is in play, namely the right to dignity, specifically the right of an individual not to endure a life of unbearable or intractable suffering against his wishes."

The QC said that "the autonomous choices we make about our death are among the most important ones we make and it is central to our sense of dignity that these choices are respected".

He told the judges: "At present the law protects the right to choose to live, to the extent that a patient may insist on continuing to receive life-sustaining treatment even where his physician considers it to be futile."

The courts are also prepared , he said, to authorise the withdrawal of life-sustaining treatment from those who lack capacity, "but who the court considers it would be inhumane to force them to continue living, thereby respecting their right of human dignity".

However, for those who have "made a competent choice to end their lives, but who cannot physically act upon that choice without medical assistance, such as Tony Nicklinson before he died and Paul Lamb, the law of murder and assisted suicide constitute, for practical purposes, an insurmountable obstacle".

He added: "To prevent them from obtaining assistance to end their life infringes not only their right to autonomy but also their right to dignity, as it thereby forced and forces them to endure a life that they consider to be overly burdensome and futile, with an extreme degree of pain, discomfort and indignity."

He said the UK was behind a number of other countries in legalising both euthansia and assisted suicide.

Mr Bowen emphasised: "We do not suggest that the law should create an untrammelled right to suicide, regardless of the vulnerability of the individual."

But the consequences of the law were felt "disproportionately" by people in situations like those of Tony Nicklinson and Paul Lamb.

He said: "Of course many others live with such conditions. There can be no suggestion that simply because a person suffers from such a condition that their life must be unbearable.

"But for many people, like the appellants, that is their experience, and their choice is that they do not wish to continue with that life.

"They have formed a competent and settled wish to end their lives, but are too sick or disabled to do so without assistance.

"As the law currently stands they must suffer in silence or make desperate attempts to kill themselves because any person who assists them - particularly any medical professional - faces prosecution and imprisonment for doing so, either for assisted suicide or murder."

Mr Bowen told the judges: "The common law of defence of necessity is of ancient origin and has been developed by the courts incrementally over time to the point where its extension to the present circumstances would be logical, foreseeable, moral, just and humane, and squarely within the constitutional powers of the courts."

In written argument before the court Philip Havers QC, for Martin, tells the judges that Martin "has never asked the courts to decriminalise assisted suicide", but "seeks clarity about how the DPP's prosecutorial discretion will be exercised".

He said: "Martin loves his family, enjoys spending time with them, and likes to read. But he finds his life and his condition following his stroke to be undignified, distressing and intolerable. He is not going to recover, and does not want to continue living like this. He wants to die."

Mr Havers submitted that "Article 8 requires the DPP to develop his policy so as to remedy a disproportionate interference with Martin's Article 8 right to decide by what means and at what point his life will end".

David Perry QC, for the Ministry of Justice, states in written submissions in relation to Mrs Nicklinson's appeal and that of Mr Lamb, that the "tragic and distressing circumstances" of the late Mr Nicklinson and of Mr Lamb "evoke the deepest sympathy".

But he says that "notwithstanding the distressing facts of their respective situations" the Ministry of Justice submits that the High Court "correctly dismissed" the claim for declarations.

Mr Perry argues: "As it concluded, the law in this area is well-established. There is no defence of necessity to a charge of murder, or assisted suicide, if a doctor were to have terminated, or assisted in the termination of the life of Tony Nicklinson.

"The state of the criminal law in this respect does not violate the right to respect for private life under Article 8 of the Convention."

Mr Perry said it was for Parliament to decide on the existing legal framework "reflecting social and moral policy" - for example the law on assisted suicide.

It was then for the courts to apply that legal framework to the facts of a particular case.